1. Field of the Invention
The present invention relates to a device for connecting a tube to a port in a housing. More particularly, the present invention relates to a connecting block for connecting a conduit tube of an air-conditioning circuit to a port associated with an accessory, such as an expansion unit or compressor of a refrigerant circuit of the type typically used in automotive vehicle air-conditioning systems.
2. Description of the Prior Art
Prior to the present invention, multiple types of tube mounting assemblies have been proposed for connecting a refrigerant line to a device of an air-conditioning circuit, such as a compressor, expansion unit or other known device.
It is known in the art to connect refrigerant hoses to the discharge port or the inlet port of a refrigerant compressor evaporator or other device within an air-conditioning circuit using a tube fitting having one end thereof fixed to the flexible hose and its other end connected to the compressor. Such a tube fitting connection is typically made either by means of a male-female threaded tube coupling or it may be fixed, as by brazing, to a compressor connector block which would also have a short pilot tube fixed therein.
Additionally, it is also known that the tube can be adapted to enter a correspondingly sized hole or port in a connector block which is then fixed by a connecting means such as a threaded bolt or spanner clamp to the port in the compressor. However, this type of connection has its drawbacks with respect to the proper departure orientation of the tube fitting relative to the compressor, the limited availability of space in the engine compartment of the automotive vehicle and the significant weight associated with such devices. These types of tube fitting connections have drawbacks in that they have a significant number of potential leakage paths for the escape of the refrigerant fluid. Finally, with these prior art tube fitting connections a significant amount of machining is required to fabricate the male-female threaded tube coupling or to fabricate the compressor connector block and its associated components.
Accordingly, different types of solutions to the problems associated with the prior art devices have been proposed. For example, U.S. Pat. No. 3,869,152 to DeVincent et al discloses a tube mounting assembly for mounting a tube to a refrigerant compressor wherein the tube has an upset annular bead adjacent its free end which is sandwiched between the legs of a fold-over clamp against which an O-ring seal encircling the free end of the tube is seated to provide a seal. A pair of slotted tube mounting brackets are mounted in interlocking relationship with each other about each tube on the opposite sides of the fold-over clamp from the O-ring seal and then the entire assembly is secured to the housing of the compressor using a bolt.
Similar to the above patent is U.S. Pat. No. 3,929,356 to DeVincent et al. The '356 reference discloses that the upset annular bead on the end of the tube is received in a stepped bore opening of a connecting block and then a spring retainer clip is removably inserted in a transverse slot from a position out of interference engagement with the annular bead on the tube to a position in which it engages the opposite side of the bead. An O-ring is sandwiched between the upset annular bead and a step portion of the stepped bore opening of the passage in the connecting block in order to lock and effect sealing of the tube in the block. The '356 reference further discloses that the block may be sealed and attached to the housing of a compressor. Both of the above references disclose a means for connecting a tube to the housing of an air-conditioning compressor which requires a multitude of intricately formed parts which add significantly to the cost and weight of the overall design of the tube connecting assembly.
A further solution to a tube mounting assembly is U.S. Pat. No. 3,869,153 to DeVincent et al. The '153 patent proposes a tube mounting assembly in which the end of the tube having the annular upset bead adjacent the pilot end of the tube is sandwiched between a mounting plate, which is slotted at opposite ends to receive the tubes, and a centrally apertured yoke on each tube encircling the pilot end thereof, each yoke having spaced apart legs clamped around the side edges of the mounting plate. The '153 reference further discloses that each yoke is welded or brazed to the annular upset bead of the tube with which it is associated in order to effect a fluid-tight seal between the elements and to prevent axial or rotative movement of the yoke relative to the tube. Thus, the '153 reference requires the welding of parts and significantly more weight than is desirable for use in certain applications in order to achieve the mounting of the tubes to the housing of the compressor of the air conditioning system.
From the above, it is clear that there is a continuing need to provide a tube mounting assembly which is lighter, less costly, has the ability to allow for reorientation of the tubes or can prevent rotation of the tube during installation and is simple to install. This is especially true when one considers the changing environments in which air-conditioning systems are used in automotive vehicles. Continuously, space is becoming more and more limited for such parts and air-conditioning systems are being used in a variety of new and different ways. For example, more automotive vehicles are now employing a second evaporator in the rear of the vehicle in order to provide effective air-conditioning to the passengers located in the rear of the vehicle, such as in a minivan.
In order to provide such a device at an economical cost, it is necessary to extend the circuit of the standard air-conditioning system to include the additional evaporator located at the rear of the vehicle to accommodate the occupants in the rear of the vehicle. This means extending both the suction and liquid lines of the standard air-conditioning system to the evaporator located in the rear of the vehicle. On some vehicles lengths in excess of 9 to 10 feet of tubing may be required to reach the rear evaporator. Additionally, in order to conserve space and to meet applicable standards, it is necessary to have the suction and liquid lines conform to the underside of the vehicle, thereby requiring that the suction and liquid line tubes have intricate convoluted shapes.
During the course of shipping these parts it is desirable to keep each associated suction line and liquid line together to make it easy to ensure that the appropriate suction line tube and compatible liquid line tube is correctly installed in each vehicle. In the past, this has been done by initially putting the mounting block over the tubes and then while the tubes are inserted in the mounting block bending the tubes into their desired shape for mounting on the vehicle. However, with the tubes mounted in the mounting block it is difficult and time consuming to bend the tubes into their final form. Additionally, with mounting blocks of the prior art, the holes are drilled completely through the mounting block in order to retain the tube within the mounting block during shipping making it difficult to service an installed line.
In the instances in which the mounting block has a passage which extends from a side of the block for receiving the tube, the means for retaining the tube in the block are complicated, expensive, prone to leakage and do not have the ability to choose between allowing for rotational movement of the tubes or preventing rotational movement of the tube with respect to the block as desired. Thus, it is necessary to provide a means for retaining the tubes within the mounting block which does not significantly add to the cost or the weight of the mounting block and which accommodates for rotational displacement of the tubes with respect to the mounting block.
As discussed above, U.S. Pat. No. 3,869,153 to DeVincent et al discloses a tube mounting assembly having slotted holes in the mounting block for receiving the tubes therein and further discloses a U-shaped yoke used for retaining the tubes in the slotted passages of the mounting plate. However, the yoke of the '153 patent significantly adds to the weight and cost of the assembly due to its size and detailed configuration which requires additional costs, materials and assembly time. Thus, there is still a need for an improved tube mounting assembly which will allow for matching of the tubes, without first being mounted in the mounting plate; will receive the tubes after they have been bent and configured for a particular application; will function to associate a suction line tube with a liquid line tube during shipping and packaging; which has significantly less weight and is less costly and will allow for, when necessary or desirable, reorientation of the tubes during installation in order to account for variances in the orientation of the mounting assembly over the significant lengths required in vehicle installations.